Optical module

ABSTRACT

An optical module includes a shell, a circuit board, a base, a laser assembly, a silicon optical chip and a protective cover. The laser assembly and the silicon optical chip are located on the base. The protective cover covers on the circuit board. The laser assembly and a wiring region of the laser assembly and/or the silicon optical chip and a wiring region of the silicon optical chip are encapsulated between the protective cover and the circuit board. The shell includes at least one heat conduction column, the at least one heat conduction column is disposed on an inner wall of the shell and is in thermal conductive connection with the laser assembly and/or the silicon optical chip. The protective cover includes at least one escape opening that allow the at least one heat conduction column to pass and enter an inside of the protective cover.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 17/235,367, filed on Apr. 20, 2021, pending, whichis a continuation-in-part of International Application No.PCT/CN2020/133868, with an international filing date of 4 Dec. 2020, andclaims priority to Chinese Patent Application No. 202010317005.2, filed21 Apr. 2020; and this application is a continuation-in-part ofInternational Application No. PCT/CN2019/127211, with an internationalfiling date of 20 Dec. 2019, which claims the priority to Chinese PatentApplication No. 201910199334.9, filed 15 Mar. 2019, Chinese PatentApplication No. 201910199347.6, filed 15 Mar. 2019, and Chinese PatentApplication No. 201910199953.8, filed 15 Mar. 2019. The entire contentsof the foregoing applications are hereby incorporated by referenceherein.

TECHNICAL FIELD

The present application relates to the field of optical fibercommunication, and in particular, to an optical module.

BACKGROUND

Optical communication technology is used in cloud computing, mobileInternet, video conference and other new services and applications. Inoptical communication, an optical module is a tool for achievinginterconversion between an optical signal and an electrical signal, andis one of key components in an optical communication device. At present,the use of a silicon optical chip to achieve the interconversion betweenthe optical signal and the electrical signal has become a mainstreamsolution adopted by a high-speed optical module.

SUMMARY

Some embodiments of the present disclosure provide an optical module.The optical module includes a shell, a circuit board, a base, a laserassembly, a silicon optical chip and a protective cover.

The circuit board is located within the shell. The base is located onthe circuit board or in a through hole of the circuit board. The laserassembly is located on the base, is electrically connected to thecircuit board, and is configured to provide light. The silicon opticalchip is located on the base, electrically connected to the circuit boardand optically connected to the laser assembly, and is configured toreceive the light, and modulate the light to form a first opticalsignal. The protective cover covers on the circuit board. The laserassembly and a wiring region of the laser assembly are encapsulatedbetween the protective cover and the circuit board, and the protectivecover is configured to protect electrical connection wires between thelaser assembly and the circuit board; and/or, the silicon optical chipand a wiring region of the silicon optical chip are encapsulated betweenthe protective cover and the circuit board, and the protective cover isconfigured to protect electrical connection wires between the siliconoptical chip and the circuit board. The shell includes at least one heatconduction column, the at least one heat conduction column is disposedon an inner wall of the shell and is in thermal conductive connectionwith the laser assembly and/or the silicon optical chip, and each heatconduction column is configured to conduct the heat inside the shell tothe shell. The protective cover includes at least one escape openingthat allow the at least one heat conduction column to pass and enter aninside of the protective cover.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to describe technical solutions in the present disclosure moreclearly, accompanying drawings to be used in some embodiments of thepresent disclosure will be introduced briefly below. Obviously, theaccompanying drawings to be described below are merely accompanyingdrawings of some embodiments of the present disclosure, and a person ofordinary skill in the art may obtain other drawings according to thesedrawings. In addition, the accompanying drawings to be described belowmay be regarded as schematic diagrams, and are not limitations on actualsizes of a product, actual processes of a method and actual timings ofsignals to which the embodiments of the present disclosure relate.

FIG. 1A is a schematic diagram showing a connection relationship of anoptical communication system, in accordance with some embodiments;

FIG. 1B is a schematic diagram showing a connection relationship ofanother optical communication system, in accordance with someembodiments;

FIG. 2 is a schematic diagram showing a structure of an optical networkterminal, in accordance with some embodiments;

FIG. 3A is a schematic diagram showing a structure of an optical module,in accordance with some embodiments;

FIG. 3B is a schematic diagram showing a structure of another opticalmodule, in accordance with some embodiments;

FIG. 4A is a schematic diagram showing an exploded structure of theoptical module shown in FIG. 3A;

FIG. 4B is a schematic diagram showing an exploded structure of theoptical module shown in FIG. 3B;

FIG. 5A is a sectional view of an optical module, in accordance withsome embodiments;

FIG. 5B is an enlarged view of a portion C in FIG. 5A;

FIG. 6A is a schematic diagram showing an assembly relationship among acircuit board, a silicon optical chip and a laser assembly in an opticalmodule, in accordance with some embodiments;

FIG. 6B is a schematic diagram showing an exploded structure of anassembly relationship between a silicon optical chip and a laserassembly in an optical module, in accordance with some embodiments;

FIG. 6C is a schematic diagram showing another exploded structure of anassembly relationship between a silicon optical chip and a laserassembly in an optical module, in accordance with some embodiments;

FIG. 7A is a schematic diagram showing an assembly relationship betweena circuit board and a protective cover in an optical module, inaccordance with some embodiments;

FIG. 7B is a schematic diagram of a circuit board without a protectivecover in an optical module, in accordance with some embodiments;

FIG. 7C is a schematic diagram showing a structure of a protective coverin an optical module, in accordance with some embodiments;

FIG. 8A is a schematic diagram showing an exploded structure of a laserassembly in an optical module, in accordance with some embodiments;

FIG. 8B is a schematic diagram showing an exploded structure of anotherlaser assembly in an optical module, in accordance with someembodiments;

FIG. 8C is a schematic diagram showing an assembly relationship betweena silicon optical chip and a laser assembly in an optical module, inaccordance with some embodiments;

FIG. 9 is a schematic diagram of an optical path between a laserassembly and a silicon optical chip in an optical module, in accordancewith some embodiments;

FIG. 10A is a simplified schematic diagram of the optical path shown inFIG. 9 ;

FIG. 10B is a simplified schematic diagram of another optical pathdifferent from the optical path shown in FIG. 9 ;

FIG. 11 is a portion sectional view of an optical module, in accordancewith some embodiments;

FIG. 12A is a schematic diagram showing an assembly relationship among abase, a silicon optical chip and a laser assembly in an optical module,in accordance with some embodiments;

FIG. 12B is a schematic diagram showing an exploded structure of anassembly relationship among a base, a silicon optical chip and a laserassembly in an optical module, in accordance with some embodiments;

FIG. 12C is a schematic diagram showing another exploded structure of anassembly relationship among a base, a silicon optical chip and a laserassembly in an optical module, in accordance with some embodiments; and

FIG. 12D is a schematic diagram of an upper box of a laser assembly inan optical module, in accordance with some embodiments.

DETAILED DESCRIPTION

Technical solutions in some embodiments of the present disclosure willbe described clearly and completely below with reference to theaccompanying drawings. Obviously, the described embodiments are merelysome but not all embodiments of the present disclosure. All otherembodiments obtained by a person of ordinary skill in the art based onthe embodiments of the present disclosure shall be included in theprotection scope of the present disclosure.

Unless the context requires otherwise, the term “comprise” and otherforms thereof such as the third-person singular form “comprises” and thepresent participle form “comprising” throughout the description and theclaims are construed as open and inclusive, i.e., “including, but notlimited to”. In the description, the terms such as “one embodiment”,“some embodiments”, “exemplary embodiments”, “example”, “specificexample” or “some examples” are intended to indicate that specificfeatures, structures, materials or characteristics related to theembodiment(s) or example(s) are included in at least one embodiment orexample of the present disclosure. Schematic representations of theabove terms do not necessarily refer to the same embodiment(s) orexample(s). In addition, the specific features, structures, materials orcharacteristics may be included in any one or more embodiments orexamples in any suitable manner.

Hereinafter, the terms such as “first”, “second” and “third” are usedfor descriptive purposes only, and are not to be construed as indicatingor implying the relative importance or implicitly indicating the numberof indicated technical features. Thus, features defined as “first”,“second” and “third” may explicitly or implicitly include one or more ofthe features. In the description of the embodiments of the presentdisclosure, the term “a plurality of” means two or more unless otherwisespecified.

Hereinafter, orientations or positional relationships indicated by theterms “center”, “upper”, “lower”, “front”, “rear”, “left”, “right”,“vertical”, “horizontal”, “top”, “bottom”, “inner”, “outer”, etc. arebased on orientations or positional relationships shown in the drawings,merely to facilitate and simplify the description of the presentdisclosure, but not to indicate or imply that the referred devices orelements must have a particular orientation, or must be constructed oroperated in a particular orientation. Therefore, these terms cannot beconstrued as limitations on the present disclosure.

In the description of some embodiments, the terms “connected” and“electrically connected” and their extensions may be used. For example,the term “connected” may be used in the description of some embodimentsto indicate that two or more components are in direct physical orelectric contact with each other. For another example, the term“electrically connected” may be used in the description of someembodiments to indicate that two or more components are in directelectric contact. However, the term “electrically connected” may alsomean that two or more components are not in direct contact with eachother, but still cooperate or interact with each other. The embodimentsdisclosed herein are not necessarily limited to the content herein.

The phrase “at least one of A, B and C” has a same meaning as the phrase“at least one of A, B or C”, and they both include the followingcombinations of A, B and C: only A, only B, only C, a combination of Aand B, a combination of A and C, a combination of B and C, and acombination of A, B and C.

The phrase “A and/or B” includes the following three combinations: onlyA, only B, and a combination of A and B.

In addition, the use of the phrase “based on” means openness andinclusiveness, since a process, step, calculation or other action thatis “based on” one or more of the stated conditions or values may, inpractice, be based on additional conditions or values exceeding thosestated.

The term “about”, “substantially” and “approximately” as used hereinincludes a stated value and an average value within an acceptable rangeof deviation of a particular value determined by a person of ordinaryskill in the art, considering measurement in question and errorsassociated with measurement of a particular quantity (i.e., limitationsof a measurement system).

In optical communication technology, an optical signal is used to carryinformation to be transmitted, and the optical signal carrying theinformation is transmitted to an information processing device such as acomputer through an information transmission device such as an opticalfiber or an optical waveguide to complete the transmission of theinformation. Since the optical signal has a characteristic of passivetransmission when being transmitted through the optical fiber or theoptical waveguide, low-cost and low-loss information transmission may beachieved. In addition, it will be noted that, a signal transmitted bythe information transmission device such as the optical fiber or theoptical waveguide is an optical signal, while a signal that can berecognized and processed by the information processing device such asthe computer is an electrical signal. Therefore, in order to establishinformation connection between the information transmission device suchas the optical fiber or the optical waveguide and the informationprocessing device such as the computer, interconversion between theelectrical signal and the optical signal needs to be achieved.

An optical module implements a function of interconversion between theoptical signal and the electrical signal in the field of optical fibercommunication technology. The optical module includes an optical portand an electrical port. The optical port is configured to implementoptical communication between the optical module and the informationtransmission device such as the optical fiber or the optical waveguide.The electrical port is configured to implement electrical connectionbetween the optical module and an optical network terminal (e.g., anoptical modem). The electrical connection is mainly to implement powersupply, transmission of an I2C signal, transmission of a data signal andgrounding. The optical network terminal transmits the electrical signalto the information processing device such as the computer through anetwork cable or wireless fidelity (Wi-Fi).

FIG. 1A is a schematic diagram showing a connection relationship of anoptical communication system in accordance with some embodiments, andFIG. 1B is a schematic diagram showing a connection relationship ofanother optical communication system in accordance with someembodiments. As shown in FIGS. 1A and 1B, the optical communicationsystem mainly includes a remote server 1000, a local informationprocessing device 2000, an optical network terminal 100, an opticalmodule 200, an optical fiber 101, and a network cable 103.

One terminal of the optical fiber 101 is connected to the remote server1000, and another terminal is connected to the optical module 200. Theoptical fiber itself may support long-distance signal transmission, suchas several-kilometer (6-kilometer to 8-kilometer) signal transmission.Based on this, if a repeater is used, infinite-distance transmission maybe achieved theoretically. Therefore, in a typical optical communicationsystem, a distance between the remote server 1000 and the optical module200 may typically reach several kilometers, tens of kilometers, orhundreds of kilometers.

One terminal of the network cable 103 is connected to the localinformation processing device 2000, and another terminal is connected tothe optical network terminal 100. The local information processingdevice 2000 is at least one of the followings: a router, a switch, acomputer, a mobile phone, a tablet computer, or a television.

A physical distance between the remote server 1000 and the opticalnetwork terminal 100 is greater than a physical distance between thelocal information processing device 2000 and the optical networkterminal 100. Connection between the local information processing device2000 and the remote server 1000 is implemented with the optical fiber101 and the network cable 103; and connection between the optical fiber101 and the network cable 103 is implemented with the optical networkterminal 100 into which the optical module 200 is inserted.

The optical module 200 has an optical port and an electrical port. Theoptical port of the optical module 200 is accessed to the optical fiber101 to establish bidirectional optical signal connection with theoptical fiber 101; and the electrical port of the optical module 200 isaccessed to the optical network terminal 100 to establish bidirectionalelectrical signal connection with the optical network terminal 100.Interconversion between the optical signal and the electrical signal isachieved by the optical module 200, so that information connectionbetween the optical fiber 101 and the optical network terminal 100 isestablished. That is to say, the optical signal from the optical fiber101 is converted into an electrical signal by the optical module 200 andthen input into the optical network terminal 100, and the electricalsignal from the optical network terminal 100 is converted into anoptical signal by the optical module 200 and then input into the opticalfiber 101. Since the optical module 200 is a tool for achieving theinterconversion between the optical signal and the electrical signal,and has no function of processing data, the information does not changein the above photoelectric conversion process.

The optical network terminal 100 has an optical module interface 102,and the optical module interface 102 is configured to access the opticalmodule 200, so that the bidirectional electrical signal connectionbetween the optical network terminal 100 and the optical module 200 isestablished; and the optical network terminal 100 has a network cableinterface 104, and the network cable interface 104 is configured toaccess the network cable 103, so that bidirectional electrical signalconnection between the optical network terminal 100 and the networkcable 103 is established. That is, connection between the optical module200 and the network cable 103 is established through the optical networkterminal 100. That is to say, the optical network terminal 100 maytransmit a signal from the optical module 200 to the network cable 103,and transmit a signal from the network cable 103 to the optical module200. Therefore, the optical network terminal 100, as a master monitor ofthe optical module 200, may monitor operation of the optical module 200.FIGS. 1A and 1B show optical network terminals 100 in two differentforms. In addition to the optical network terminal 100, the mastermonitor of the optical module 200 may further include an optical lineterminal (OLT).

A bidirectional signal transmission channel between the remote server1000 and the local information processing device 2000 has beenestablished through the optical fiber 101, the optical module 200, theoptical network terminal 100, and the network cable 103.

FIG. 2 is a schematic diagram showing a structure of an optical networkterminal. In order to clearly show a connection relationship between theoptical module 200 and the optical network terminal 100, FIG. 2 onlyshows a structure of the optical network terminal 100 related to theoptical module 200. As shown in FIG. 2 , the optical network terminal100 includes a circuit board 105, a cage 106 and a heat sink 107. Thecage 106 is disposed on a surface of the circuit board 105, and a cavityenclosed by both of the cage 106 and the circuit board 105 forms theoptical module interface 102; the circuit board 105 has an electricalconnector, the cage 106 wraps the electrical connector therein, and theelectrical connector is configured to access the electrical port of theoptical module 200; and the heat sink 107 is disposed on the cage 106,and the heat sink 107 has protruding structures such as fins capable ofincreasing a heat dissipation area.

The optical module 200 is inserted into the cage 106 of the opticalnetwork terminal 100, the optical module 200 is fixed by the cage 106,and heat generated by the optical module 200 is conducted to the cage106 and is dissipated through the heat sink 107. After the opticalmodule 200 is inserted into the cage 106, the electrical port of theoptical module 200 is connected to the electrical connector in the cage106, so that the bidirectional electrical signal connection between theoptical module 200 and the optical network terminal 100 is established.In addition, the optical port of the optical module 200 is connected tothe optical fiber 101, so that the bidirectional optical signalconnection between the optical module 200 and the optical fiber 101 isestablished.

FIG. 3A is a diagram showing a structure of an optical module inaccordance with some embodiments, and FIG. 4A is an exploded view of theoptical module shown in FIG. 3A. FIG. 3B is a diagram showing astructure of another optical module in accordance with some embodiments,and FIG. 4B is an exploded view of the optical module shown in FIG. 3B.As shown in FIGS. 3A to 3B and 4A to 4B, the optical module 200 includesan upper shell 201, a lower shell 202, a circuit board 300, a siliconoptical chip 400, and a laser assembly 500.

The upper shell 201 and the lower shell 202 form a shell with a wrappingcavity. In some embodiments, the upper shell 201 covers the lower shell202 to form the wrapping cavity with two openings. The circuit board300, the silicon optical chip 400 and the laser assembly 500 are locatedin the wrapping cavity, and an outer contour of the wrapping cavity isgenerally in a rectangular parallelepiped shape.

In some embodiments, as shown in FIGS. 4A and 4B, the upper shell 201includes a top plate 2011, the lower shell 202 includes a bottom plate2021 and two lower side plates 2022 located on both sides of the bottomplate 2021 and disposed perpendicular to the bottom plate 2021, and thetop plate 2011 covers the two lower side plates 2022 of the lower shell202 to form the wrapping cavity. In some other embodiments, the uppershell 201 includes a top plate and two upper side plates located on bothsides of the top plate and disposed perpendicular to the top plate; andthe lower shell 202 includes a bottom plate and two lower side plateslocated on both sides of the bottom plate and disposed perpendicular tothe bottom plate, and the two upper side plates are combined with thetwo lower side plates respectively to achieve that the upper shell 201covers the lower shell 202.

The two openings may be openings 204 and 205 at both ends of the shellwhich are in a same direction, or may be two openings of the shell whichare in different directions. The same direction refers to a direction inwhich a connection line between the openings 204 and 205 is located, andthis direction is the same as a longitudinal direction of the opticalmodule 200. The different directions mean that the direction in whichthe connection line between the openings 204 and 205 is located is notthe same as the longitudinal direction of the optical module 200. Forexample, the opening 204 is located at an end (a left end of FIG. 3A ora right end of FIG. 3B) of the optical module 200, and the opening 205is located at a side (an upper side of FIG. 3A or FIG. 3B) of theoptical module 200. One of the openings is the electrical port 204, aconnecting finger of the circuit board 300 extends from the electricalport 204, and definitions for pins of the connecting finger form variousindustry protocols and specifications, and the connecting finger isconfigured to be inserted into the master monitor (e.g., the opticalnetwork terminal 100); and another opening is the optical port 205,which is configured to access an external optical fiber (the opticalfiber 101), so that the external optical fiber is connected to thesilicon optical chip 400 inside the optical module 200.

By using an assembly mode of combining the upper shell 201 and the lowershell 202, it is possible to facilitate installation of the circuitboard 300, the silicon optical chip 400 and the laser assembly 500 intothe wrapping cavity, and the upper shell 201 and the lower shell 202 mayform encapsulation protection for these devices. In addition, whenassembling components such as the circuit board 300, the silicon opticalchip 400 and the laser assembly 500, it is possible to facilitatearrangement of positioning structures, heat dissipation structures andelectromagnetic shielding structures of these components, and it ispossible to facilitate implementation of automated production.

In some embodiments, the upper shell 201 and the lower shell 202 aremade of a metal material to facilitate electromagnetic shielding andheat dissipation.

In order to achieve higher heat dissipation efficiency and facilitatethe dissipation of the heat inside the optical module 200, in someembodiments, at least one heat conduction column is disposed on an innerwall of the shell of the optical module 200, and the heat conductioncolumn is configured to conduct the heat inside the shell of the opticalmodule 200 to the shell of the optical module 200, so as to facilitatethe dissipation of the heat inside the optical module 200.

FIG. 5A is a sectional view of an optical module in accordance with someembodiments, and FIG. 5B is an enlarged view of a portion C in FIG. 5A.For example, as shown in FIGS. 5A and 5B, the laser assembly 500 and thesilicon optical chip 400 are disposed on a side of the circuit board 300close to the upper shell 201, and the upper shell 201 includes a firstheat conduction column 2013 and a second heat conduction column 2014. Anorthogonal projection of the first heat conduction column 2013 on thecircuit board 300 and an orthogonal projection of the laser assembly 500on the circuit board 300 are at least partially overlapped, and anorthogonal projection of the second heat conduction column 2014 on thecircuit board 300 and an orthogonal projection of the silicon opticalchip 400 on the circuit board are at least partially overlapped.However, it is not limited thereto. In a case where the laser assembly500 and the silicon optical chip 400 are disposed on a side of thecircuit board 300 close to the lower shell 202, the lower shell 202includes the first heat conduction column 2013 and the second heatconduction column 2014.

An outer surface of the laser assembly 500 proximate to the upper shell201 is provided with a first heat conduction pad 207, and a free end ofthe first heat conduction column 2013 is in contact connection with thelaser assembly 500 through the first heat conduction pad 207. An outersurface of the silicon optical chip 400 proximate to the upper shell 201is provided with a transimpedance amplifier 410 and a modulator driver420 (for the transimpedance amplifier 410 and the modulator driver 420,reference may also be made to FIGS. 6A to 6C and 7A to 7B), a secondheat conduction pad 208 is disposed on a side of the transimpedanceamplifier 410 and a side of the modulator driver 420 that are away fromthe silicon optical chip 400, and a free end of the second heatconduction column 2014 is in contact connection with the transimpedanceamplifier 410 and the modulator driver 420 through the second heatconduction pad 208.

Here, the first heat conduction pad 207 is configured to improveefficiency at which heat of a box of the laser assembly 500 istransferred to the first heat conduction column 2013; and the secondheat conduction pad 208 is configured to improve efficiency at whichheat of the transimpedance amplifier 410 and the modulator driver 420 istransferred to the second heat conduction column 2014. Both the firstheat conduction pad 207 and the second heat conduction pad 208 may bemade of a thermally conductive adhesive.

In this case, heat generated by elements (laser chips, etc.) inside thelaser assembly 500 may be transferred to the first heat conductioncolumn 2013 through the first heat conduction pad 207, then transferredto the upper shell 201 of the optical module 200 through the first heatconduction column 2013, and finally dissipated through the upper shell201. Heat generated by the transimpedance amplifier 410 and themodulator driver 420 is transferred to the second heat conduction column2014 through the second heat conduction pad 208, then transferred to theupper shell 201 of the optical module 200 through the second heatconduction column 2014, and finally dissipated through the upper shell201.

Therefore, the heat inside the optical module 200 may be transferred tothe upper shell 201 of the optical module 200 through the first heatconduction column 2013 and the second heat conduction column 2014, andthen the heat is conducted to an outside of the optical module 200, soas to avoid concentrated accumulation of the heat inside the opticalmodule. Moreover, since the upper shell 201 of the optical module 200 iscloser to the heat sink 107 on the cage 106 than the lower shell 202 ofthe optical module 200, conducting the heat inside the optical module200 to the upper shell 201 may achieve heat dissipation at higherefficiency than conducting the heat inside the optical module 200 to thelower shell 202.

In some embodiments, the orthogonal projection of the first heatconduction column 2013 on the circuit board 300 is greater than or equalto the orthogonal projection of the laser assembly 500 on the circuitboard 300 to increase a heat conduction area and improve a heatdissipation efficiency; and the orthogonal projection of the second heatconduction column 2014 on the circuit board 300 may be greater than orequal to the orthogonal projection of the silicon optical chip 400 onthe circuit board 300 to increase a heat conduction area and improve aheat dissipation efficiency.

In addition, a sectional area of the free end of the first heatconduction column 2013 is smaller than that of a fixed end of the firstheat conduction column 2013 at a contact position between the first heatconduction column 2013 and the upper shell 201, and a sectional area ofthe first heat conduction column 2013 gradually increases from the freeend of the first heat conduction column 2013 to the fixed end of thesame; and a sectional area of the free end of the second heat conductioncolumn 2014 is smaller than that of a fixed end of the second heatconduction column 2014 at a contact position between the second heatconduction column 2014 and the upper shell 201, and a sectional area ofthe second heat conduction column 2014 gradually increases from the freeend of the second heat conduction column 2014 to the fixed end of thesame. For example, the first heat conduction column 2013 and the secondheat conduction column 2014 are in a shape of a truncated cone or atruncated pyramid.

The first heat conduction column 2013 and the second heat conductioncolumn 2014 may be integrally formed with the upper shell 201, or may beseparate components and are assembled with the upper shell 201.

Based on this, in some embodiments, an upper surface of the upper shell201 proximate to the cage 106 is provided with fins, and the fins are incontact with the cage 106 to increase the heat dissipation area andassist in the heat dissipation.

In some embodiments, the optical module 200 further includes anunlocking component 203. The unlocking component 203 is located on anouter wall of the shell of the optical module 200, and is configured toimplement or release a fixed connection between the optical module 200and the master monitor (e.g., the optical network terminal 100). FIGS.3A and 4A show an example of the unlocking component 203.

In some embodiments, the unlocking component 203 is located on an outerwall of the lower shell 202, and pulling a tail end of the unlockingcomponent 203 may move the unlocking component 203 on the outer wall ofthe lower shell 202. When the optical module 200 is inserted into themaster monitor, the optical module 200 is engaged with the cage 106 ofthe master monitor by the unlocking component 203. In this case, pullingthe unlocking component 203 may change a connection relationship betweenthe unlocking component 203 and the master monitor, thereby releasingthe engagement between the optical module 200 and the master monitor, sothat the optical module 200 may be drawn out of the cage 106 of themaster monitor.

The circuit board 300 includes circuit wires, electronic elements (e.g.,capacitors, resistors, triodes, and metal-oxide-semiconductorfield-effect transistors (MOSFET transistors)), and chips (e.g., amicrocontroller unit (MCU), a clock and data recovery (CDR) chip, apower management chip, and a digital signal processing (DSP) chip). Theelectronic elements, the chips and other components in the circuit board300, and the silicon optical chip 400, the laser assembly 500 and othercomponents on the circuit board 300 are connected together through thecircuit wires according to a circuit design, so as to implementfunctions of power supply, electrical signal transmission, grounding andthe like. The silicon optical chip 400 and the laser assembly 500 aredisposed on a same side of the circuit board 300. At least a part of theelectronic components and the chips are configured to be connected tothe silicon optical chip 400 or the laser assembly 500 through circuitwires, thereby supplying power to the silicon optical chip 400 or thelaser assembly 500, or providing the grounding function for the siliconoptical chip 400 or the laser assembly 500, or performing the electricalsignal transmission with the silicon optical chip 400 or the laserassembly 500. For example, the power management chip supplies power tothe laser assembly 500 through circuit wires, and the triodes or theMOSFET transistors are used as switches to control the laser assembly500 to or not to emit light through circuit wires.

The circuit board 300 is generally a rigid circuit board, and the rigidcircuit board may also implement a bearing function due to itsrelatively hard material, for example, the rigid circuit board maystably bear the electronic elements and the chips; in a case where thesilicon optical chip 400 and the laser assembly 500 are located on thecircuit board 300, the rigid circuit board may also provide stablebearing; and the rigid circuit board may also be inserted into the cage106 of the master monitor.

For example, a surface of a tail end of the circuit board 300 has theconnecting finger 301, the connecting finger 301 is composed of aplurality of pins separate from each other, the circuit board 300 isinserted into the cage 106, and is conductively connected to theelectrical connector in the cage 106 through the connecting finger 301.The connecting finger 301 may be disposed on only one surface (e.g., anupper surface shown in FIGS. 4A and 4B) of the circuit board 300, or maybe disposed on both upper and lower surfaces of the circuit board toadapt to an occasion with a demand for a large number of pins. Theconnecting finger 301 is configured to establish electrical connectionwith the master monitor, and the electrical connection may be used toachieve power supply, grounding, I2C communication, data signalcommunication, etc.

Of course, flexible circuit boards are also used in some optical modules200. As a supplement to the rigid circuit board, a flexible circuitboard is generally used in conjunction with the rigid circuit board. Forexample, the rigid circuit board may be connected to the silicon opticalchip 400 and the laser assembly 500 by using the flexible circuit boardinstead of the circuit wires.

The silicon optical chip 400 and the laser assembly 500 are disposed onthe circuit board 300, and are electrically connected to the circuitboard 300. There is an optical connection between the silicon opticalchip 400 and the laser assembly 500. Light emitted by the laser assembly500 enters the silicon optical chip 400, and the silicon optical chip400 receives the light from the laser assembly 500. In some embodiments,the laser assembly 500 provides light with a single wavelength to thesilicon optical chip 400, the light has stable power and has no data,and the silicon optical chip 400 modulates the light to load data thatneeds to be transmitted into the light. In addition, the silicon opticalchip 400 also receives light carrying data from the outside of theoptical module, the silicon optical chip 400 converts the light into ancurrent signal and transmits the current signal to the transimpedanceamplifier 410, and the transimpedance amplifier 410 converts the currentsignal of the silicon optical chip 400 into a differential voltage andtransmits the differential voltage to the DSP chip for further process,so as to extract the data in the light. That is to say, both themodulation of the light emitted by the optical module 200 and thedemodulation of the light received by the optical module 200 arecompleted by the optical module 200.

In a feasible implementation, the circuit board 300 provides a datasignal from the master monitor to the silicon optical chip 400, and thesilicon optical chip 400 modulates the data signal into the light toform an optical signal, the optical signal is then transmitted to theoutside of the optical module 200. In another feasible implementation,an optical signal from the outside of the optical module 200 isconverted into a current signal through the silicon optical chip 400,and the current signal is transmitted to the transimpedance amplifier410 and converted into a differential voltage by the transimpedanceamplifier 410, the differential voltage is processed by the DSP chip toget an electrical signal, and the electrical signal is output to themaster monitor through the circuit board 300.

In order to achieve the above modulation and demodulation of the opticalsignal, there is a need to assemble the circuit board 300, the siliconoptical chip 400 and the laser assembly 500 according to predeterminedpositions to form a predetermined optical propagation path.

The light propagation path is very sensitive to a positionalrelationship between the silicon optical chip 400 and the laser assembly500. However, the circuit board 300 is formed by stacking multiplelayers of materials, each layer of material has a thermal expansioncoefficient respectively, and different thermal expansion coefficientsmay cause deformations to different degrees at different positions ofthe circuit board 300, thereby causing a change of relative positionbetween the silicon optical chip 400 and the laser assembly 500, whichis not conductive to achievement of the predetermined opticalpropagation path. Therefore, in some embodiments, as shown in FIG. 4A,the silicon optical chip 400 and the laser assembly 500 are firstlymounted on a base 302, which is a plate-like structure made of a samematerial, and then the base 302 is disposed in the circuit board 300.Since the silicon optical chip 400 and the laser component 500 aredisposed on a same base 302, and deformations generated at differentpositions of the base 302 are the same when the base 302 is heated, thedeformations generated when the base 302 is heated have a same influenceon the laser assembly 500 and the silicon optical chip 400, the changeof the relative position between the silicon optical chip 400 and thelaser assembly 500 caused by the deformations of the circuit board 300may be reduced, stability of an alignment state of the laser assembly500 and the silicon optical chip 400 is high, and assembly requirementsfor the laser assembly 500 and the silicon optical chip 400 are lowered.

A material of the base 302 is not limited. For example, a thermalexpansion coefficient of the material of the base 302 is similar to athermal expansion coefficient of a material of the silicon optical chip400 and/or the laser assembly 500; and for example, the material of thesilicon optical chip 400 is silicon, and the material of the laserassembly 500 is a Kovar alloy, and the material of the base 302 issilicon or glass. The Kovar alloy is also referred to asiron-nickel-cobalt alloy, or iron-nickel-cobalt glass sealing alloy, andgenerally contains 29% nickel and 18% cobalt, and the rest is iron. Athermal expansion coefficient of the Kovar alloy is reduced due toaddition of cobalt, and is similar to that of glass, and the Kovar alloyis suitable for sealing with glass.

It can be seen from the above that, the silicon optical chip 400 and thelaser assembly 500 are generally disposed on a same side of the circuitboard 300. In this case, there are various positional relationshipsbetween the base 302 and the circuit board 300.

In some embodiments, as shown in FIGS. 4A and 5A to 5B, the circuitboard 300 has a through hole 302 a penetrating an upper and lowersurfaces of the circuit board 300, the base 302 is disposed in thethrough hole 302 a, and the silicon optical chip 400 and/or the laserassembly 500 are disposed on the base 302. In this way, it is possiblenot only to facilitate to reduce influence of the deformations of thecircuit board 300 on the relative position between the silicon opticalchip 400 and the laser assembly 500, but also to facilitate theelectrical connection between the silicon optical chip 400 and/or thelaser assembly 500 and the circuit board 300. In addition, the siliconoptical chip 400 and/or the laser assembly 500 may dissipate heat to thebase, so that the base 302 has both a support effect and a heatdissipation effect.

The base 302 includes a clamping portion 302A and a support step 302B.The support step 302B is disposed around the clamping portion 302A, theclamping portion 302A is clamped in the through hole 302 a in thecircuit board 300, and the support step 302B supports the circuit board300. The clamping portion 302A is a structure in the dashed box in FIG.5B, and the support step 302B is a structure below the dashed box inFIG. 5B. In addition, in order to enhance reliability of connectionbetween the base 302 and the circuit board 300, the support step 302B ofthe base 302 and the circuit board 300 may be adhesively fixed by usinga glue.

A thermal conductivity of the material of the base 302 is higher than athermal conductivity of a material of the circuit board 300; forexample, the base 302 is a silicon base or a glass base; and for anotherexample, the base 302 is a copper alloy base with a thermal conductivitygreater than that of the circuit board 300. Such a manner that the base302 is disposed in the through hole 302 a may facilitate the dissipationof the heat generated by the laser assembly 500 and the silicon opticalchip 400.

In a case where the circuit board 300 has the through hole 302 apenetrating the upper and lower surfaces of the circuit board, a surfaceof the base 302 away from the silicon optical chip 400 and the laserassembly 500 is in contact with the shell (e.g., the lower shell 202) ofthe optical module 200, so as to transfer the heat inside the opticalmodule 200 to the shell of the optical module 200 through the base 302,and then conduct the heat to the outside of the optical module 200 toavoid the concentrated accumulation of the heat inside the opticalmodule 200.

In addition, in some embodiments, as shown in FIGS. 5A to 5B, thesurface of the base 302 away from the silicon optical chip 400 and thelaser assembly 500 is further provided with a third heat conduction pad209, and the base 302 is in contact with the shell (e.g., the lowershell 202) of the optical module 200 through the third heat conductionpad 209. The third heat conduction pad 209 is configured to improveefficiency at which heat of the base 302 is transferred to the shell ofthe optical module 200, and the third heat conduction pad 209 may bemade of a thermally conductive adhesive.

In some other embodiments, the circuit board 300 is provided with nothrough hole, and the base 302 is disposed on the circuit board 300. Inyet some other embodiments, the circuit board 300 is provided with acounterbore (i.e., a blind hole), and the base 302 is embedded in theblind hole in the circuit board 300. In order to achieve opticalcoupling between the silicon optical chip 400 and the laser assembly500, a light exit surface of the laser assembly 500 and a light incidentsurface of the silicon optical chip 400 need to be at a same height. Theoptical coupling here refers to a phenomenon in which two or moreoptical elements are in an interfitting relationship, and light istransmitted from one optical element into another optical element. Sincethe silicon optical chip 400 is manufactured by using thin-film growthand etching processes, it has a high integration level and a relativelysmall volume; while the laser assembly 500 has a relatively largevolume. If a bottom face of the silicon optical chip 400 and a bottomface of the laser assembly 500 are disposed in a same plane of the base302, the height of the light exit surface of the laser assembly 500 willbe greater than the height of the light incident surface of the siliconoptical chip 400.

As shown in FIGS. 4A and 5A to 5B, the base 302 includes a first stepface 3021 and a second step face 3022. The first step face 3021 and thesecond step face 3022 are located on a surface of the base 302 on whichthe silicon optical chip 400 and the laser assembly 500 are disposed(both the first step face 3021 and the second step face 3022 being asurface of the clamping portion 302A), and in a case where the surfaceof the base 302 away from the silicon optical chip 400 and the laserassembly 500 is a bottom face, a height of the first step face 3021 fromthe bottom face is smaller than a height of the second step face 3022from the bottom face. Providing the laser assembly 500 on the first stepface 3021 and providing the silicon optical chip 400 on the second stepface 3022 may balance a difference between the heights of the siliconoptical chip 400 and the laser assembly 500.

It will be noted that, the light exit surface of the laser assembly 500is a surface of the laser assembly 500 proximate to the silicon opticalchip 400, and the light incident surface of the silicon optical chip 400is a surface of the silicon optical chip 400 proximate to the laserassembly 500.

FIG. 6A is a schematic diagram showing an assembly relationship of acircuit board, a silicon optical chip and a laser assembly, inaccordance with some embodiments. FIG. 6B is a schematic diagram showingan exploded structure of an assembly relationship between a siliconoptical chip and a laser assembly, in accordance with some embodiments,and FIG. 6C is a schematic diagram showing another exploded structure ofan assembly relationship between a silicon optical chip and a laserassembly, in accordance with some embodiments. As shown in FIG. 6A, thesilicon optical chip 400 and the laser assembly 500 are disposed on thebase 302, so that the light exit surface of the laser assembly 500 isoptically coupled to the light incident surface of the silicon opticalchip 400.

In some embodiments, in order to allow light to smoothly enter thesilicon optical chip 400 from the laser assembly 500, the light incidentsurface of the silicon optical chip 400 proximate to the laser assembly500 has a first optical waveguide end facet 401, a second opticalwaveguide end facet 402 and a third optical waveguide end facet 403, andeach optical waveguide end facet is corresponding to at least oneoptical channel. In some embodiments, the second optical waveguide endfacet 402 is corresponding to two optical channels. Among these opticalwaveguide end facets, the second optical waveguide end facet 402 isoptically coupled to the laser assembly 500, and is configured toreceive light without carrying a signal emitted by the laser assembly500; the first optical waveguide end facet 401 is configured to transmitan optical signal obtained after the modulation by the silicon opticalchip 400 to the outside of the optical module 200; and the third opticalwaveguide end facet 403 is configured to receive an optical signal fromthe outside the optical module 200 and transmit the optical signal tothe silicon optical chip 400, so that the silicon optical chip 400converts the optical signal into an electrical signal.

For example, the optical module 200 further includes a first opticalfiber array 303A, a first optical fiber ribbon 304A, a second opticalfiber array 303B, and a second optical fiber ribbon 304B. The firstoptical fiber ribbon 304A is a thin flat strip formed by curing aplurality of optical fibers 305A arranged in parallel by usingultraviolet light, and the second optical fiber ribbon 304B is a thinflat strip formed by curing a plurality of optical fibers 305B arrangedin parallel by using the ultraviolet light. One end of the first opticalfiber array 303A is optically coupled to the first optical waveguide endfacet 401, and another end is connected to the optical fiber socket 306shown in FIG. 4A or 4B through the first optical fiber ribbon 304A; andone end of the second optical fiber array 303B is optically coupled tothe third optical waveguide end facet 403, and another end is connectedto the optical fiber socket 306 shown in FIG. 4A or FIG. 4B through thesecond optical fiber ribbon 304B. The optical fiber socket 306 forms theoptical port 205 of the optical module 200, and is configured to connectthe optical fiber 101 outside the optical module 200.

As shown in FIG. 6C, the first optical fiber array 303A includes anupper substrate 307A and a lower substrate 308A. The lower substrate308A is provided with grooves, the optical fibers 305A are disposed inthe grooves, and the upper substrate 307A covers the lower substrate308A on a side of the lower substrate 308A where the grooves areprovided. Similarly, the second optical fiber array 303B includes anupper substrate 307B and a lower substrate 308B. The lower substrate308B is provided with grooves, the optical fibers 305B are disposed inthe grooves, and the upper substrate 307B covers the lower substrate308B on a side of the lower substrate 308B where the grooves areprovided.

The light emitted by the laser assembly 500 enters a waveguide insidethe silicon optical chip 400 through the second optical waveguide endfacet 402, then enters the first optical fiber array 303A through thefirst optical waveguide end facet 401 after being modulated into anoptical signal by the silicon optical chip 400, and then is transmittedto the optical fiber socket 306 through the first optical fiber array303A and the first optical fiber ribbon 304A, thereby achieving a lightemission process of the optical module 200. The external optical signalenters the second optical fiber array 303B through the optical fibersocket 306 and the second optical fiber ribbon 304B, then is transmittedto the silicon optical chip 400 through the third optical waveguide endfacet 403 and its corresponding waveguide, and then is converted by thesilicon optical chip 400 to form an electrical signal, thereby achievinga light receiving process of the optical module 200.

In some embodiments, as shown in FIGS. 6A to 6C, the light incidentsurface 404 of the silicon optical chip 400 is not perpendicular to anaxial direction A of the laser assembly 500, and the axial direction Aof the laser assembly 500 is shown by the two-dot chain line in FIG. 6A.For example, the light incident surface 404 of the silicon optical chip400 and a side face opposite to the light incident surface 404 areparallel to each other, and the light exit surface 520 of the laserassembly 500 is not perpendicular to the axial direction of the laserassembly 500. In this case, the silicon optical chip 400 is obliquelydisposed with respect to the laser assembly 500. Accordingly, neither ofside faces of the first optical fiber array 303A and the second opticalfiber array 303B that are coupled to the silicon optical chip 400 areperpendicular to the axial direction A of the laser assembly 500. Thelight emitted from the light exit surface 520 of the laser assembly 500is refracted at the light incident surface 404 of the silicon opticalchip 400 to meet requirements of the silicon optical chip 400 for alight incident angle, so that the light smoothly enters the siliconoptical chip 400, which will be described in detail later.

It will be understood that, the silicon optical chip 400 and the circuitboard 300 need to be electrically connected, and a manner in which thesilicon optical chip 400 is electrically connected to the circuit board300 is not exclusive. In some embodiments, the silicon optical chip 400is provided with bonding pads, and the silicon optical chip 400 iselectrically connected to the circuit board 300 through the bonding padsby means of wire bonding. For example, the bonding pads of the siliconoptical chip 400 are electrically connected to the circuit board 300 bymeans of gold wire bonding.

During encapsulation of the shell of the optical module 200 or duringuse of the optical module 200, due to tiny and fragile gold wires (asmall wire diameter) and small spacing between wires caused by densewiring, the gold wires are very prone to phenomena such as deformation,damage and collapse, thereby causing defects such as a short circuit oran open circuit, and further affecting a quality of the optical signal.

Based on this, in some embodiments, as shown in FIGS. 7A to 7C, theoptical module 200 further includes a protective cover 600, which isconfigured to protect electrical connection wires between the siliconoptical chip 400 and the circuit board 300. For example, the protectivecover 600 covers on the circuit board 300 and forms an enclosed spacewith the circuit board 300, and the silicon optical chip 400 and awiring region of the silicon optical chip 400 are both encapsulated inthe enclosed space.

In addition, since the laser assembly 500 is also electrically connectedto the circuit board 300 by means of wire bonding, in some embodiments,the protective cover 600 is further configured to protect electricalconnection wires between the laser assembly 500 and the circuit board300. That is to say, the protective cover 600 covers on the circuitboard 300 and forms the enclosed space with the circuit board 300, andthe silicon optical chip 400 and the wiring region of the siliconoptical chip 400, and the laser assembly 500 and a wiring region of thelaser assembly 500 are all encapsulated in the enclosed space.

It will be noted that, “being encapsulated in the enclosed space” refersto an assembly manner by which the silicon optical chip 400 and thewiring region of the silicon optical chip 400, and the laser assembly500 and the wiring region of the laser assembly 500 are in clearance fitwith the protective cover 600 in the enclosed space formed by theprotective cover 600 and the circuit board 300.

In some embodiments, the protective cover 600 is bonded to the circuitboard 300 through a glue. In some other embodiments, as shown in FIGS.7A to 7C, the protective cover 600 is fixedly connected to the circuitboard 300 through at least two fixing pins 700. For example, the circuitboard 300 includes fixing holes 309, the protective cover 600 includesvia holes 602, and the fixing pins 700 pass through the via holes 602 tobe fitted with the fixing holes 309 to fix the protective cover 600 onthe circuit board 300.

It will be noted that, the fixing holes 309 in the circuit board 300need to escape the circuit wires, the electronic elements (e.g., thecapacitors, the resistors, the triodes and the MOSFET transistors) andthe chips (e.g., the MCU, the CDR chip, the power management chip andthe DSP chip) and other components on the circuit board 300.

The protective cover 600 may be made of a transparent resin materialsuch as transparent Polyetherimide (PEI) or Polycarbonate (PC). The PEIis high-temperature resistant and has strong high-temperature stability.The PEI has a heat deformation temperature of 220° C., and may be usedfor a long time at an operation temperature of −160° C. to 180° C.; andthe PEI also has good flame retardancy (a flame rating being UL94-V-0,and UL94 being American standard for the flame rating), and goodchemical-reaction resistance and electrical insulation properties. Inaddition, the PEI may also be processed into a thin-walled product witha small wall thickness.

In some embodiments, an inner surface and an outer surface of theprotective cover 600 are both mirror-polished, so that when theelectrical connection wires between the silicon optical chip 400 and thecircuit board 300 are damaged and/or the electrical connection wiresbetween the laser assembly 500 and the circuit board 300 are damaged inthe optical module 200, a position where the damage occurs may bevisually identified without a need to disassemble the protection cover600.

As described above, in some embodiments, the shell of the optical module200 includes at least one heat conduction column. In this case, theprotective cover 600 further includes at least one escape opening thatallow the at least one heat conduction column to pass and enter aninside of the protective cover 600. For example, the upper shell 201includes the first heat conduction column 2013 and the second heatconduction column 2014, and the protective cover 600 includes a firstescape opening 603 and a second escape opening 604. The first heatconduction column 2013 passes through the first escape opening 603 to bein thermal conductive connection with the laser assembly 500, and thesecond heat conduction column 2014 passes through the second escapeopening 604 to be in thermal conductive connection with thetransimpedance amplifier 410 and the modulator driver 420.

The first escape opening 603 includes a first inclined surface 6031, thefirst inclined surface 6031 is located at an edge of an inner wall ofthe first escape opening 603, and the first inclined surface 6031 mayenlarge a sectional area of the first escape opening 603. That is, in adirection of an axis S1 of the first escape opening 603 and away fromthe circuit board 300 (or the laser assembly 500), the sectional area ofthe first escape opening 603 gradually increases, which facilitates thefirst heat conduction column 2013 to pass. In addition, the firstinclined surface 6031 may also match the inner wall of the first escapeopening 603 with an outer wall of the first heat conducting column 2013,thereby making it easier for the first heat conduction column 2013 topass. The second escape opening 604 includes a second inclined surface6041, the second inclined surface 6041 is located at an edge of an innerwall of the second escape opening 604, and the second inclined surface6041 may enlarge a sectional area of the second escape opening 604. Thatis, in a direction of an axis S2 of the second escape opening 604 andaway from the circuit board 300 (or the silicon optical chip 400), thesectional area of the second escape opening 604 gradually increases,which facilitates the second heat conduction column 2014 to pass. Inaddition, the second inclined surface 6041 may also match the inner wallof the second escape opening 604 with an outer wall of the second heatconduction column 2014, thereby making it easier for the second heatconduction column 2014 to pass.

In some embodiments, a bottom of the edge of the inner wall of the firstescape opening 603 in the protective cover 600 compresses the laserassembly 500; and a bottom of the edge of the inner wall of the secondescape opening 604 compresses the silicon optical chip 400, or thebottom of the edge of the inner wall of the second escape opening 604compresses the silicon optical chip 400 by compressing thetransimpedance amplifier 410 and the modulator driver 420.

For the structures of the first escape opening 603 and the second escapeopening 604, reference may also be made to FIGS. 5A to 5B.

A conventional silicon optical chip is mainly composed of a lightsource, a modulator, a detector, a passive waveguide and other elements,and these elements are integrated on a same silicon-based substrate.Through modulation of light by the modulator, the silicon optical chipmay convert an electrical signal to an optical signal. It will be notedthat, in some embodiments of the present disclosure, since a material ofthe silicon-based substrate used in the silicon optical chip 400 is notan ideal light-emitting material for laser chips, the silicon opticalchip 400 does not have a light source integrated therein, and the laserassembly 500 (including laser chips, which will be described in detaillater) serves as a light source to provide light with the siliconoptical chip 400.

In some embodiments, a modulator in the silicon optical chip 400 is aMach-Zehnder interferometer, through which modulation of the opticalsignal is achieved. In detail, according to an interference principle oflight, the Mach-Zehnder interferometer splits an input light beam intotwo light beams with a same wavelength and a same intensity, and a phasedifference of the two light beams is changed by a change of anelectrical signal which is applied externally, and when the two lightbeams are merged again through interference, the intensity of the mergedlight will be changed according to the change of the electrical signalapplied externally. This is equivalent to converting the electricalsignal into the optical signal, thereby achieving the modulation of thelight.

The transimpedance amplifier 410 on the silicon optical chip 400 isconfigured to convert a current signal generated by the silicon opticalchip 400 into a differential voltage and transmit the differentialvoltage to the DSP chip for further process, so as to extract the datain the light.

The modulator driver 420 on the silicon optical chip 400 is configuredto amplify an electrical signal from the DSP chip and transmit theelectrical signal to the Mach-Zehnder interferometer to modulate lightwithout carrying a signal within the silicon optical chip 400, so as tocovert the electrical signal into an optical signal.

The following describes how the laser assembly 500 provides two lightbeams with a same or similar wavelength and a same or similar intensitywith the silicon optical chip 400. FIG. 8A is a schematic diagramshowing an exploded structure of a laser assembly in an optical module,in accordance with some embodiments, and FIG. 8B is a schematic diagramshowing an exploded structure of another laser assembly in an opticalmodule, in accordance with some embodiments.

In some embodiments, as shown in FIGS. 8A and 8B, the laser assembly 500includes an upper box 501, a lower box 502, a light transmitting member508, conductive substrates 503A and 503B, and laser chips 504A and 504B.

For example, the upper box 501 and the lower box 502 are combined toform a cavity with two openings 530 and 540, and the two openings 530and 540 are located at both ends of the laser assembly 500 in the axialdirection A (for the axial direction A, reference may be made to FIG.6A), and includes a first opening 530 located in an optical path wherethe light emitted by the laser chips 504A and 504B is directed towardthe silicon optical chip 400, and a second opening 540 away from thesilicon optical chip 400. The light transmitting member 508 is locatedbetween the upper box 501 and the lower box 502, and is configured toenclose the first opening 530 of the laser assembly 500, and the lightemitted by the laser chips 504A and 504B enters the silicon optical chip400 after passing through the light transmitting member 508.

The upper box 501 and the lower box 502 may have various structures toform the cavity. As shown in FIG. 8A, the upper box 501 includes onlyone upper cover plate, and the lower box 502 includes a lower coverplate and two opposite side plates located at two opposite long sides ofthe lower cover plate and perpendicular to the lower cover plate. FIG.8B discloses a structure different from this. As shown in FIG. 8B, theupper box 501 includes an upper cover plate and two opposite side plateslocated at two opposite long sides of the upper cover plate andperpendicular to the upper cover plate, and the lower box 502 includesonly one lower cover plate. Although not shown, it may be obtained that,in some embodiments, the upper box 501 includes the upper cover plateand the two opposite side plates located at the two opposite long sidesof the upper cover plate and perpendicular to the upper cover plate, andthe lower box 502 includes the lower cover plate and the two oppositeside plates located at the two opposite long sides of the lower coverplate and perpendicular to the lower cover plate.

The conductive substrates 503A and 503B are partially located in thecavity, and partially extend out of the second opening 540 and arelocated outside the cavity; and the laser chips 504A and 504B arerespectively disposed on the conductive substrates 503A and 503B and arelocated in the cavity. In this case, the laser assembly 500 furtherincludes at least one blocking member 509 or 510. The at least oneblocking member 509 or 510 is located between the upper box 501 and thelower box 502, and is configured to enclose the second opening 540 ofthe laser assembly 500.

For example, the at least one blocking member 509 or 510 includes afirst blocking member 509 and a second blocking member 510, and theconductive substrates 503A and 503B are located between the firstblocking member 509 and the second blocking member 510 to enclose thesecond opening 540 of the laser assembly 500. As shown in FIG. 8A, thefirst blocking member 509 is located between the conductive substrates503A and 503B and the upper box 501, and the second blocking member 510is located between the conductive substrates 503A and 503B and the lowerbox 502. Or, as shown in FIG. 8B, the first blocking member 509 islocated between the conductive substrates 503A and 503B and the lowerbox 502, and the second blocking member 510 is located between theconductive substrates 503A and 503B and the upper box 501.

Portions of the conductive substrates 503A and 503B extending out of thesecond opening 540 may be electrically connected to the circuit board300 by means of bonding. It will be noted that, in some embodiments, theconductive substrates 503A and 503B are entirely located in the cavity,and wires for connecting the conductive substrates 503A and 503B extendout of the second opening 540 and are electrically connected to thecircuit board 300, thereby achieving the electrical connection betweenthe conductive substrates 503A and 503B and the circuit board 300.

The upper box 501, the lower box 502, the light transmitting member 508,and the at least one blocking member 509 or 510 form a relatively closedcavity, so as to provide a relatively sealed environment for otherelements (e.g., the laser chips 504A and 504B) inside the laser assembly500, prevent moisture and the like from affecting these elements andaffecting the optical path, and protect the elements inside the laserassembly 500.

In some embodiments, a material of the at least one blocking member isat least one of ceramic, Kovar alloy, solidified glue or die-cast metal.A material of the conductive substrates is metalized ceramic, and theconductive substrates each include a ceramic plate and a circuit patternformed on a surface of the ceramic plate according to differentelectrical connection requirements. A material of the light transmittingmember is glass or solidified glue. The upper box 501 and the lower box502 may be made of a thermally conductive material, such as copperalloy.

It will be noted that, the laser assembly 500 is not limited to the useof the upper box 501, the lower box 502, the light transmitting member508 and the at least one blocking member 509 or 510 to form therelatively closed cavity, and the laser assembly 500 may also form therelatively closed cavity by means of the base 302. In some embodiments,as shown in FIGS. 12A to 12D, the laser assembly 500 includes the upperbox 501, the light transmitting member 508, the conductive substrates503A and 503B, and the laser chips 504A and 504B.

For example, the upper box 501 and the base 302 are combined to form acavity with an opening 550, and the opening 550 is located in theoptical path where the light emitted by the laser chips 504A and 504B isdirected toward the silicon optical chip 400. The conductive substrates503A and 503B are disposed in the cavity and are mounted on the base302, and the laser chips 504A and 504B are respectively disposed onsurfaces of the conductive substrates 503A and 503B away from the base302. The light transmitting member 508 is located between the base 302and the upper box 501, and is configured to enclose the opening 550 ofthe laser assembly 500. The light emitted by the laser chips 504A and504B enters the silicon optical chip 400 after passing through the lighttransmitting member 508. The upper box 501 and the base 302 may be fixedby using a glue. With such an arrangement, the conductive substrates503A and 503B and the laser chips 504A and 504B are directly wrapped bythe upper box 501 and the base 302, which facilitates encapsulation ofthe laser assembly 500.

The conductive substrates 503A and 503B need to be electricallyconnected to the circuit board 300 by means of bonding. Therefore, aslot 560 is disposed between the upper box 501 and the base 302. Theslot 560 allows the conductive substrates 503A and 503B to extend out ofthe cavity formed by the upper box 501 and the base 302, or allows thewires for electrically connecting the conductive substrates 503A and503B to the circuit board 300 to extend out of the cavity formed by theupper box 501 and the base 302.

In order to form the opening 550 and the slot 560, as shown in FIG. 12Bor 12D, the upper box 501 includes a cover plate 5011, and a first sideplate 5012, a second side plate 5013 and a third side plate 5014 thatare disposed around the cover plate 5011. The first side plate 5012 andthe second side plate 5013 are oppositely disposed on both sides of thecover plate 5011 in a length direction thereof, and the third side plate5014 is disposed on a side of the cover plate 5011 in a width directionthereof. An upper surface of the base 302 includes a first region 30211,a second region 30212 and a third region 30213 that are disposed side byside on the first step face 3021, and a fourth region 30221 disposed onthe second step face 3022 of the base 302. An arrangement direction ofthe first region 30211, the second region 30212 and the third region30213 is perpendicular to an arrangement direction of the first stepface 3021 and the second step face 3022. The first region 30211 isconfigured to carry the first optical fiber array 303A, the secondregion 30212 is configured to fix and carry the laser assembly 500, thethird region 30213 is configured to carry the second optical fiber array303B, and the fourth region 30221 is configured to carry the siliconoptical chip 400.

A first gap 30215 is disposed between the first region 30211 and thesecond region 30212, and a second gap 30216 is disposed between thesecond region 30212 and the third region 30213. A bottom of the firstside plate 5012 is clamped in the first gap 30215, and a bottom of thesecond side plate 5013 is clamped in the second gap 30216, therebyachieving installation and fixation of the upper box 501. As such, theopening 550 is formed in the optical path where the light emitted by thelaser chips 504A and 504B is directed toward the silicon optical chip400, and the slot 560 is formed in a direction of the laser chips 504Aand 504B away from the silicon optical chip 400.

In some embodiments, widths of the first gap 30215 and the second gap30216 are slightly greater than thicknesses of the first side plate 5012and the second side plate 5013, which not only facilitates theinstallation and fixation of the upper box 501, but also reduces heatconducted to the first region 30211 and the third region 30213 from thesecond region 30212 and generated by the laser assembly 500 on thesecond region 30212, thereby achieving heat insulation between thesecond region 30212 and both the first region 30211 and the third region30213. The laser assembly 500 includes the laser chips 504A and 504B.The laser chips 504A and 504B generate a large amount of heat duringoperation, and are main heat sources of the optical module 200. Thefirst gap 30215 and the second gap 30216 may effectively blockhorizontal transfer of the heat from the second region 30212 to thefirst region 30211 and the third region 30213. As will be mentionedlater, the heat generated by the laser chips 504A and 504B is mainlyvertically transmitted to the upper shell 201 of the optical module 200by means of the upper box 501.

As further shown in FIGS. 8A to 8C, the conductive substrates 503A and503B include a first conductive substrate 503A and a second conductivesubstrate 503B. The laser chips 504A and 504B include a first laser chip504A and a second laser chip 504B. The first laser chip 504A is disposedon the first conductive substrate 503A, and the second laser chip 504Bis disposed on the second conductive substrate 503B. In FIG. 8B, thefirst laser chip 504A is disposed on a surface of the first conductivesubstrate 503A close to the lower box 502, and the second laser chip504B is disposed on a surface of the second conductive substrate 503Bclose to the lower box 502. The first laser chip 504A and the secondlaser chip 504B are invisible since they are blocked by the firstconductive substrate 503A and the second conductive substrate 503B. Insome embodiments, there may be only one conductive substrate, and thefirst laser chip 504A and the second laser chip 504B are disposed on asame conductive substrate.

The laser assembly 500 further includes a first collimating lens 505A, asecond collimating lens 505B, a first focusing lens 506A, a secondfocusing lens 506B, and an isolator 507. The first laser chip 504A andthe second laser chip 504B, the first collimating lens 505A and thesecond collimating lens 505B, the first focusing lens 506A and thesecond focusing lens 506B, and the isolator 507 are all located in therelatively closed cavity formed by the upper box 501, the lower box 502,the light transmitting member 508, and the at least one blocking member509 or 510. Moreover, the first collimating lens 505A and the secondcollimating lens 505B, the first focusing lens 506A and the secondfocusing lens 506B, and the isolator 507 are all disposed on the lowerbox 502.

The first collimating lens 505A, the first focusing lens 506A, theisolator 507 and the light transmitting member 508 are sequentiallyarranged in a light exit direction of the first laser chip 504A; and thesecond collimating lens 505B, the second focusing lens 506B, theisolator 507 and the light transmitting member 508 are sequentiallyarranged in a light exit direction of the second laser chip 504B. Twolight beams respectively emitted by the two laser chips 504A and 504Bshare one isolator 507 and one light transmitting member 508; and ofcourse, in some embodiments, one isolator and one light transmittingmember may be separately provided for a single light beam emitted byeach laser chip, that is, the laser assembly 500 includes two isolatorsand two light transmitting members.

It will be noted that, a layout of the elements inside the laserassembly 500 is not limited to the sequential arrangement of the firstcollimating lens 505A, the first focusing lens 506A, the isolator 507and the light transmitting member 508 in the light exit direction of thefirst laser chip 504A, and the sequential arrangement of the secondcollimating lens 505B, the second focusing lens 506B, the isolator 507and the light transmitting member 508 in the light exit direction of thesecond laser chip 504B. In some embodiments, as shown in FIGS. 12B to12C, positions of the first focusing lens 506A and the isolator 507 inthe laser assembly 500 are interchanged, and positions of the secondfocusing lens 506B and the isolator 507 in the laser assembly 500 areinterchanged. That is to say, in FIGS. 12B to 12C, the first collimatinglens 505A, the isolator 507, the first focusing lens 506A and the lighttransmitting member 508 are sequentially arranged in the light exitdirection of the first laser chip 504A; and the second collimating lens505B, the isolator 507, the second focusing lens 506B and the lighttransmitting member 508 are sequentially arranged in the light exitdirection of the second laser chip 504B.

As shown in FIGS. 8A to 8C, the light exit direction of the first laserchip 504A is parallel to the axial direction A of the laser assembly500, a single light beam emitted by the first laser chip 504A is in adivergent state, and is converged by the first collimating lens 505A toform collimated parallel light, and a parallel light may travel for along distance with low loss to meet requirements of optical path designand structural design; and the first focusing lens 506A converges thecollimated parallel light into converged light, and the converged lightreduces an area of a light spot of the single light beam, andconcentrates energy of the single light beam, which is conductive toimproving efficiency of the optical coupling between the laser assembly500 and waveguides in the silicon optical chip 400.

Similarly, the light exit direction of the second laser chip 504B isparallel to the axial direction A of the laser assembly 500, a singlelight beam emitted by the second laser chip 504B is in a divergentstate, and is converged by the second collimating lens 505B to formcollimated parallel light, and a parallel light may travel for a longdistance with low loss to meet the requirements of optical path designand structural design; and the second focusing lens 506B converges thecollimated parallel light into converged light, and the converged lightreduces an area of a light spot of the single light beam, andconcentrates energy of the single light beam, which is conductive toimproving efficiency of the optical coupling between the laser assembly500 and the silicon optical chip.

The first laser chip 504A and the second laser chip 504B emit two lightbeams, respectively, with a same or similar wavelength and withoutcarrying signals. The two light beams with the same or similarwavelength and the same or similar intensity are modulated respectivelyby the Mach-Zehnder interferometer in the silicon optical chip 400.

It can be seen from the above that, the light emitted by the first laserchip 504A is directed toward the first focusing lens 506A after beingcollimated by the first collimating lens 505A, then is directed towardthe isolator 507 through the first focusing lens 506A, then is directedtoward the light transmitting member 508 through the isolator 507, andfinally exits from the laser assembly 500. By adjusting the firstfocusing lens 506A, a direction in which the light finally exits may bechanged. Similarly, the light emitted by the second laser chip 504B isdirected toward the second focusing lens 506B after being collimated bythe second collimating lens 505B, then is directed toward the isolator507 through the second focusing lens 506B, then is directed toward thelight transmitting member 508 through the isolator 507, and finallyexits from the laser assembly 500. By adjusting the second focusing lens506B, a direction in which the light finally exits may be changed.

By adjusting the first focusing lens 506A and the second focusing lens506B, the directions in which the two light beams finally exit may beseparately adjusted, which facilitates to separately achieve the opticalcoupling of the two light beams between the laser assembly 500 and thesilicon optical chip 400. Therefore, in some embodiments, the laserassembly 500 does not include the first collimating lens 505A and thesecond collimating lens 505B, and adjusts the directions in which thetwo light beams finally exit only by means of the first focusing lens506A and the second focusing lens 506B.

It will be noted that, the adjustment of the first focusing lens 506Aand the second focusing lens 506B generally needs to be performed afterthe first laser chip 504A and the second laser chip 504B are energizedto emit light. However, as shown in FIG. 8B, since the conductivesubstrates 503A and 503B are disposed on the upper box 501 through thesecond blocking member 510, and the laser chips 504A and 504B aredisposed on surfaces of the conductive substrates 503A and 503B awayfrom the upper box 501, there is a need to directly or indirectlyarrange the laser chips 504A and 504B, the conductive substrates 503Aand 503B, and the second blocking member 510 on the upper box 501 first,and then assemble the upper box 501 with the lower box 502. In this way,before the upper box 501 and the lower box 502 are assembled, theoptical path of the laser assembly 500 is not completely formed, and thelaser chips 504A and 504B cannot be energized to emit light; and afterthe upper box 501 and the lower box 502 are assembled, the positions ofthe first focusing lens 506A and the second focusing lens 506B in thelaser assembly 500 cannot be moved.

Based on this, as shown in FIGS. 8B and 11 , the upper box 501 of thelaser assembly 500 includes an adjustment through hole 512, and thefirst focusing lens 506A and the second focusing lens 506B are below theadjustment through hole 512. That is, an orthogonal projection of theadjustment through hole 512 on the base 302 at least partially coversorthogonal projections of the first focusing lens 506A and the secondfocusing lens 506B on the base 302.

In this way, after the upper box 501 and the lower box 502 areassembled, the laser chips 504A and 504B are energized to emit light,and an adjustment tool outside the laser assembly 500 may extend intothe laser assembly 500 through the adjustment through hole 512, so as toadjust the positions of the first focusing lens 506A and the secondfocusing lens 506B. For example, the positions or angles of the firstfocusing lens 506A and the second focusing lens 506B are changed tochange positions where the light beams exit, so that the light beams arealigned with a waveguide corresponding to the second optical waveguideend facet 402 on the light incident surface 404 of the silicon opticalchip 400.

In a case where the upper box 501 of the laser assembly 500 includes theadjustment through hole 512, in order to achieve enclosing of the laserassembly 500, in some embodiments, the laser assembly 500 furtherincludes a block 511, which may block the adjustment through hole 512.

In addition, in order to adjust heights of the focusing lenses, in someembodiments, a spacer block 513 is disposed between the first focusinglens 506A and the lower box 502 and between the second focusing lens506B and the lower box 502.

The isolator 507 receives the light from the first focusing lens 506Aand the second focusing lens 506B, and allows the light to pass in asingle direction and cut off in an opposite direction. That is, theisolator 507 allows the light to enter the silicon optical chip 400 fromthe laser assembly 500, but does not allow the light to enter the laserassembly 500 from the silicon optical chip 400. Therefore, the isolator507 functions to isolate the light, and prevents the light from beingreflected back into the laser chips 504A and 504B.

The light beam emitted by the laser assembly 500 enters the siliconoptical chip 400. In order to prevent the light beam from beingreflected when entering the silicon optical chip 400, in turn to reduceloss of optical power caused by the reflection, it is required that thelight beam should enter the silicon optical chip 400 at an angle that isnot perpendicular to the light incident surface 404 of the siliconoptical chip 400.

In some embodiments, the light exit direction of the laser assembly 500is changed depending on a structure of the light transmitting member508, so as to meet the requirements of the silicon optical chip 400 fora light incident angle. As shown in FIGS. 8A and 8B, for example, thelight transmitting member 508 is a hexahedron and includes twonon-parallel but opposite side faces 5081 and 5082, one side face 5081is a light incident surface, and another side face 5082 is a light exitsurface; and it can be understood that, the light exit surface 5082 ofthe light transmitting member 508 and the light exit surface 520 of thelaser assembly 500 are a same light exit surface. The light incidentsurface 5081 and the light exit surface 5082 of the light transmittingmember 508 are not parallel, that is, they form an included angle of not0°, and the light exit surface 5082 of the light transmitting member 508is significantly inclined with respect to the light incident surface5081.

As shown in FIG. 9 , the light beams enter the light transmitting member508 at an angle perpendicular to the light incident surface 5081 of thelight transmitting member 508, then are refracted at the light exitsurface 5082, and then are refracted again by the light incident surface404 of the silicon optical chip 400, so as to meet the requirements ofthe silicon optical chip 400 for a light incident angle. It will benoted that, inside the laser assembly 500, the directions of the lightemitted by the laser chips 504A and 504B may or may not be changedduring the light's travel. In FIG. 9 , the light incident surface 5081of the light transmitting member 508 is perpendicular to the light exitdirections of the laser chips 504A and 504B, and the directions of thelight emitted by the laser chips 504A and 504B are not changed duringits travel to the light transmitting member 508.

The light incident surface 5081 and the light exit surface 5082 of thelight transmitting member 508 are not parallel, so that after the lightenters into the light incident surface 5081 of the light transmittingmember 508 and exits out of the light exit surface 5082, the propagationdirection of the light is aligned with the second optical waveguide endfacet 402 of the silicon optical chip 400. Since the light transmittingmember 508 is an element through which the light beam inevitably passes,and is an element through which the light beam finally passes in thelaser assembly 500, the use of the light transmitting member 508 tochange the transmission direction of the light may relatively simplymeet the requirements of the silicon optical chip 400 for a lightincident angle.

In FIG. 9 , the light emitted by the second laser chip 504B isperpendicular to a light exit surface of the second laser chip 504B, andis parallel to the axial direction A of the laser assembly 500; thelight incident surface 5081 of the light transmitting member 508 isperpendicular to the propagation direction of the light emitted by thesecond laser chip 504B, and the light emitted by the second laser chip504B is directed toward the light incident surface 5081 of the lighttransmitting member 508 in an initial propagation direction, and reachesthe light exit surface 5082 of the light transmitting member 508 in theinitial propagation direction; the light is refracted at the light exitsurface 5082 of the light transmitting member 508, and the refractedlight enters a gap between the light transmitting member 508 and thesilicon optical chip 400, and reaches the light incident surface 404 ofthe silicon optical chip 400; and the light enters the silicon opticalchip 400 after being refracted again at the light incident surface 404of the silicon optical chip 400.

FIG. 10A is a simplified schematic diagram of the optical path shown inFIG. 9 . Only the lower box 502, the second laser chip 504B, the lighttransmitting member 508 and the silicon optical chip 400 are shown inFIG. 10A. The optical path shown in FIG. 10A is the same as the opticalpath shown in FIG. 9 . As shown in FIG. 10A, the light exit surface ofthe second laser chip 504B is parallel to the light incident surface5081 of the light transmitting member 508, the light exit surface 5082of the light transmitting member 508 is parallel to the light incidentsurface 404 of the silicon optical chip 400, and the light incidentsurface 5081 and the light exit surface 5082 of the light transmittingmember 508 are not parallel. The light emitted by the second laser chip504B is not refracted at the light incident surface 5081 of the lighttransmitting member 508, but is refracted for a first time at the lightexit surface 5082 of the light transmitting member 508, and is refractedfor a second time at the light incident surface 404 of the siliconoptical chip 400. In some embodiments, a refractive index of thematerial of the silicon optical chip 400 is equal to or similar to arefractive index of the material of the light transmitting member 508.As a result, the light is refracted for the first time at the light exitsurface 5082 of the light transmitting member 508, and then is refractedfor the second time at the light incident surface 404 of the siliconoptical chip 400, which is equivalent to that the light enters medium B(the gap between the light transmitting member 508 and the siliconoptical chip 400) from medium A (the light transmitting member 508), andthen enters the medium A (the silicon optical chip 400) from the mediumB. Thus, an incident angle α of the light at the medium A (the siliconoptical chip 400) is equal to a refraction angle β of the light in themedium B.

The silicon optical chip 400 generally requires that the light should bedirected toward the light incident surface 404 of the silicon opticalchip 400 at an incident angle α of 11.6° (α=11.6°), and a refractionangle θ after the light enters the silicon optical chip 400 should be8°. As shown in FIG. 10A, this requires that an included angle γ betweenthe light exit direction of the second laser chip 504B and a normal lineof the light exit surface 5082 of the light transmitting member 508should be equal to 8° (γ=8°). That is, the light emitted by the secondlaser chip 504B is directed toward the light exit surface 5082 of thelight transmitting member 508 at an incident angle γ of 8° (γ=8°).

It will be understood that, if the light emitted by the second laserchip 504B is directly directed toward the light incident surface 404 ofthe silicon optical chip 400 without passing through the lighttransmitting member 508, the light emitted by the second laser chip 504Bneeds to be directed toward the light incident surface 404 of thesilicon optical chip 400 at the incident angle of 11.6°. After the lighttransmitting member 508 is used in the laser assembly 500, the incidentangle at which the light emitted by the second laser chip 504B isdirected toward the light incident surface 404 of the silicon opticalchip 400 may be changed from 11.6° to 8°, so that an angle of the lightexit direction of the second laser chip 504B with respect to the siliconoptical chip 400 is decreased, and the refraction is more favorable formaintaining a shape of a light spot of the light emitted by the secondlaser chip 504B than the reflection, so it is possible to facilitate toimprove the efficiency of the optical coupling between the laserassembly 500 and the silicon optical chip 400.

It can be understood that, the same is true for the optical path of thefirst laser chip 504A.

In the optical path shown in FIGS. 9 and 10A, the light exit directionof the second laser chip 504B is parallel to the axial direction A ofthe laser assembly 500, which facilitates manufacture of the laserassembly 500 and the optical module 200.

FIG. 10B is a simplified schematic diagram of another optical pathdifferent from the optical path shown in FIG. 9 . Only the lower box502, the second laser chip 504B, the light transmitting member 508 andthe silicon optical chip 400 are shown in FIG. 10B. As shown in FIG.10B, the light exit surface of the second laser chip 504B is parallel tothe light incident surface 5081 of the light transmitting member 508,the light exit surface 5082 of the light transmitting member 508 isparallel to the light incident surface 404 of the silicon optical chip400, and the light incident surface 5081 and the light exit surface 5082of the light transmitting member 508 are not parallel; the light emittedby the second laser chip 504B is perpendicular to the light exit surfaceof the second laser chip 504B, and is not parallel to the axialdirection A of the laser assembly 500; the light emitted by the secondlaser chip 504B is not refracted at the light incident surface 5081 ofthe light transmitting member 508, but is directed toward the lightincident surface 5081 of the light transmitting member 508 in theinitial propagation direction, and reaches the light exit surface 5082of the light transmitting member 508 in the initial propagationdirection; the light emitted by the second laser chip 504B is refractedfor the first time at the light exit surface 5082 of the lighttransmitting member 508, and the light refracted for the first timeenters the gap between the light transmitting member 508 and the siliconoptical chip 400, and reaches the light incident surface 404 of thesilicon optical chip 400; and the light enters the silicon optical chip400 after being refracted for the second time at the light incidentsurface 404 of the silicon optical chip 400.

By rotating the second laser chip 504B, the light transmitting member508 and the silicon optical chip 400 in FIG. 10A clockwise by a certainangle, the optical path shown in FIG. 10B may be obtained. This anglemay be, for example, the incident angle γ at which the light emitted bythe second laser chip 504B is directed toward the light exit surface5082 of the light transmitting member 508, and for example, γ is equalto 8° (γ=8°). Similarly, by rotating the second laser chip 504B, thelight transmitting member 508 and the silicon optical chip 400 in FIG.10B counterclockwise by a certain angle, the optical path shown in FIG.10A may be obtained.

In some embodiments, as shown in FIG. 9 , an optical glue 514 fills agap between the light exit surface 5082 of the light transmitting member508 and the light incident surface 404 of the silicon optical chip 400,so that no air exists in the gap between the light exit surface 5082 ofthe light transmitting member 508 and the light incident surface 404 ofthe silicon optical chip 400. The light directly enters the optical glue514 after exiting from the light transmitting member 508, therebypreventing the light from scattering in the gap between the light exitsurface 5082 of the light transmitting member 508 and the light incidentsurface 404 of the silicon optical chip 400 due to existence of dust inthe gap. In addition, by filling the gap with the optical glue 514, itis possible to prevent the light exit surface 5082 of the lighttransmitting member 508 and the light incident surface 404 of thesilicon optical chip 400 from being contaminated, and reliability of theproduct may be improved.

A refractive index of the optical glue 514 is greater than or equal tothe refractive index of waveguides in the silicon optical chip 400, andis less than or equal to the refractive index of the light transmittingmember 508. Generally speaking, a relationship among refractive indexesis that a refractive index of gas is less than a refractive index ofliquid, and the refractive index of the liquid is less than a refractiveindex of solid (gas<liquid<solid). Therefore, the refractive index ofthe optical glue 514 is generally greater than a refractive index ofair. For example, the refractive index of the air is 1, the refractiveindex of the silicon optical chip 400 is 1.46, the refractive index ofthe light transmitting member 508 is 1.53, and the refractive index ofthe optical glue 514 may be greater than or equal to 1.46 and less thanor equal to 1.53. For example, the refractive index of the optical glue514 is 1.46, 1.47, 1.48, 1.49, 1.50, 1.51, 1.52, or 1.53. A material ofthe optical glue 514 may be epoxy resin.

In daily use, the optical module 200 has a need for heat dissipation. Itis known that, the laser chips 504A and 504B in the laser assembly 500generate a large amount of heat during operation, and the heat mayincrease a temperature in a working environment of the laser chips 504Aand 504B, and a high temperature in the working environment may causepower of the laser chips 504A and 504B to decrease and cause thewavelength of the light beams generated by the laser chips 504A and 504Bto shift. To this end, there is a need to provide heat dissipation forthe laser chips 504A and 504B.

In some embodiments, since the upper shell 201 of the optical module 200is closer to the heat sink 107 on the cage 106 than the lower shell 202of the optical module 200, conducting the heat inside the optical module200 to the upper shell 201 may achieve heat dissipation at higherefficiency than conducting the heat inside the optical module 200 to thelower shell 202.

Based on this, as shown in FIGS. 5A to 5B, 8B and 11 , the upper box 501of the laser assembly 500 is in thermal conductive contact with theupper shell 201 of the optical module 200, the second conductivesubstrate 503B is disposed on an inner surface of the upper box 501facing the base 302 through the second blocking member 510, and thesecond laser chip 504B is disposed on the surface of the conductivesubstrate 503B away from the upper box 501. In this way, the heatgenerated by the second laser chip 504B is conducted to the upper box501 of the laser assembly 500 through the second conductive substrate503B, and then is conducted to the upper shell 201 of the optical module200 through the upper box 501 of the laser assembly 500, so that theheat generated by the second laser chip 504B is dissipated from theupper shell 201. It can be understood that, the same is true for thedissipation of the heat of the first laser chip 504A. In addition, thesecond blocking member 510 between the second conductive substrate 503Band the upper box 501 is not necessary, and whether the second blockingmember 510 needs to be used may be determined according to heatdissipation requirements and enclosing requirements of the laserassembly 500.

It can be seen from FIGS. 5A to 5B that, in a case where the outersurface of the laser assembly 500 is provided with the first heatconduction pad 207, and the upper shell 201 of the optical module 200includes the first heat conduction column 2013, heat in the upper box501 of the laser assembly 500 may be conducted to the upper shell 201 ofthe optical module 200 through the first heat conduction pad 207 and thefirst heat conduction column 2013.

In addition, in some embodiments, the circuit board 300 has the throughhole 302 a penetrating the upper and lower surfaces of the circuit board300, and the base 302 is located in the through hole 302 a. In a casewhere the surface of the base 302 away from the silicon optical chip 400and the laser assembly 500 is in thermal contact with the lower shell202 of the optical module 200, the heat generated by the silicon opticalchip 400 is mainly dissipated to the lower shell 202 of the opticalmodule 200 through the base 302.

Therefore, the heat generated by the laser assembly 500 is mainlydissipated through the upper shell 201 of the optical module 200, andthe heat generated by the silicon optical chip 400 is mainly dissipatedthrough the lower shell 202 of the optical module 200, so that the heatof the silicon optical chip 400 and the laser assembly 500 is preventedfrom being concentrated on a same side of the optical module 200, upperand lower sides of the optical module 200 are fully utilized for heatdissipation, and the heat dissipation efficiency is improved.

It can be seen from FIGS. 5A to 5B that, in a case where the siliconoptical chip 400 is provided with the transimpedance amplifier 410 andthe modulator driver 420, the second heat conduction pad 208 is disposedon the side of the transimpedance amplifier 410 and the modulator driver420 that is away from the silicon optical chip 400, and the upper shell201 of the optical module 200 includes the second heat conduction column2014, the heat in the transimpedance amplifier 410 and the modulatordriver 420 may be conducted to the upper shell 201 of the optical module200 through the second heat conduction pad 208 and the second heatconduction column 2014.

As shown in FIGS. 12B to 12C, in a case where the laser assembly 500does not include the lower box 502, the heat generated by the laserassembly 500 may also be dissipated to the lower shell 202 of theoptical module 200 through the base 302.

The foregoing descriptions are merely specific implementations of thepresent disclosure, but the protection scope of the present disclosureis not limited thereto. Any changes or replacements that a personskilled in the art could conceive of within the technical scope of thepresent disclosure shall be included in the protection scope of thepresent disclosure. Therefore, the protection scope of the presentdisclosure shall be subject to the protection scope of the claims.

What is claimed is:
 1. An optical module, comprising: a shell; a circuitboard, wherein the circuit board is located within the shell; a base,wherein the base is located on the circuit board or in a through hole ofthe circuit board; a laser assembly, wherein the laser assembly islocated on the base and electrically connected to the circuit board, andis configured to provide first light; a silicon optical chip, whereinthe silicon optical chip is located on the base, electrically connectedto the circuit board and optically connected to the laser assembly, andis configured to receive the first light, and modulate the first lightto form a first optical signal; and a protective cover, wherein theprotective cover covers on the circuit board; the laser assembly and awiring region of the laser assembly are encapsulated between theprotective cover and the circuit board, and the protective cover isconfigured to protect electrical connection wires between the laserassembly and the circuit board; and/or, the silicon optical chip and awiring region of the silicon optical chip are encapsulated between theprotective cover and the circuit board, and the protective cover isconfigured to protect electrical connection wires between the siliconoptical chip and the circuit board; wherein the shell includes at leastone heat conduction column, the at least one heat conduction column isdisposed on an inner wall of the shell and is in thermal conductiveconnection with the laser assembly and/or the silicon optical chip, andeach heat conduction column is configured to conduct the heat inside theshell to the shell; and the protective cover includes at least oneescape opening that allow the at least one heat conduction column topass and enter an inside of the protective cover.
 2. The optical moduleaccording to claim 1, wherein the at least one heat conduction columnincludes a first heat conduction column, the at least one escape openingincludes a first escape opening, and the first heat conduction columnpasses through the first escape opening to be in thermal conductiveconnection with the laser assembly; and/or the at least one heatconduction column includes a second heat conduction column, the at leastone escape opening includes a second escape opening, and the second heatconduction column passes through the second escape opening to be inthermal conductive connection with the silicon optical chip.
 3. Theoptical module according to claim 2, wherein the first escape openingincludes a first inclined surface, the first inclined surface is locatedat an edge of an inner wall of the first escape opening, and a sectionalarea of the first escape opening increases in a direction of an axis ofthe first escape opening and away from the circuit board; and/or thesecond escape opening includes a second inclined surface, the secondinclined surface is located at an edge of an inner wall of the secondescape opening, and a sectional area of the second escape openingincreases in a direction of an axis of the second escape opening andaway from the circuit board.
 4. The optical module according to claim 2,wherein an orthogonal projection of the first heat conduction column onthe circuit board and an orthogonal projection of the laser assembly onthe circuit board are at least partially overlapped; and/or anorthogonal projection of the second heat conduction column on thecircuit board and an orthogonal projection of the silicon optical chipon the circuit board are at least partially overlapped.
 5. The opticalmodule according to claim 4, wherein the orthogonal projection of thefirst heat conduction column on the circuit board is greater than orequal to the orthogonal projection of the laser assembly on the circuitboard; and/or the orthogonal projection of the second heat conductioncolumn on the circuit board may be greater than or equal to theorthogonal projection of the silicon optical chip on the circuit board.6. The optical module according to claim 2, wherein a bottom of the edgeof the inner wall of the first escape opening in the protective covercompresses the laser assembly; and/or a bottom of the edge of the innerwall of the second escape opening compresses the silicon optical chip.7. The optical module according to claim 2, wherein the silicon opticalchip is further configured to receive a second optical signal from anoutside of the optical module; the optical module further comprising: atransimpedance amplifier, wherein the transimpedance amplifier isdisposed on the silicon optical chip, and is configured to convert acurrent signal generated by the silicon optical chip based on the secondoptical signal into a differential voltage and transmit the differentialvoltage to the circuit board, so as to extract data in the secondoptical signal from the outside of the optical module; and a modulatordriver, wherein the modulator driver is disposed on the silicon opticalchip, and is configured to amplify a first electrical signal from thecircuit board and transmit the first electrical signal to the siliconoptical chip, so as to covert the first electrical signal into the firstoptical signal.
 8. The optical module according to claim 7, wherein thesecond heat conduction column passes through the second escape openingto be in thermal conductive connection with the transimpedance amplifierand the modulator driver.
 9. The optical module according to claim 8,wherein a bottom of the edge of the inner wall of the first escapeopening in the protective cover compresses the laser assembly; and/or abottom of the edge of the inner wall of the second escape openingcompresses the silicon optical chip by compressing the transimpedanceamplifier and the modulator driver.
 10. The optical module according toclaim 7, wherein the shell includes an upper shell and a lower shell,the upper shell includes the first heat conduction column and the secondheat conduction column, and the laser assembly and the silicon opticalchip are disposed on a side of the circuit board close to the uppershell.
 11. The optical module according to claim 10, wherein thetransimpedance amplifier and the modulator driver are disposed on anouter surface of the silicon optical chip proximate to the upper shell.12. The optical module according to claim 10, further comprising: afirst heat conduction pad disposed on an outer surface of the laserassembly proximate to the upper shell; and a second heat conduction paddisposed on a side of the transimpedance amplifier and a side of themodulator driver that are away from the silicon optical chip; wherein afree end of the first heat conduction column is in contact connectionwith the laser assembly through the first heat conduction pad, and afree end of the second heat conduction column is in contact connectionwith the transimpedance amplifier and the modulator driver through thesecond heat conduction pad.
 13. The optical module according to claim12, wherein the first heat conduction pad is made of a thermallyconductive adhesive, and the second heat conduction pad is made of athermally conductive adhesive.
 14. The optical module according to claim10, wherein a sectional area of a free end of the first heat conductioncolumn is smaller than that of a fixed end of the first heat conductioncolumn at a contact position between the first heat conduction columnand the upper shell, and a sectional area of the first heat conductioncolumn increases from the free end of the first heat conduction columnto the fixed end of the first heat conduction column; and a sectionalarea of a free end of the second heat conduction column is smaller thanthat of a fixed end of the second heat conduction column at a contactposition between the second heat conduction column and the upper shell,and a sectional area of the second heat conduction column increases fromthe free end of the second heat conduction column to the fixed end ofthe second heat conduction column.
 15. The optical module according toclaim 14, wherein the first heat conduction column and the second heatconduction column are in a shape of a truncated cone or a truncatedpyramid.
 16. The optical module according to claim 10, wherein the firstheat conduction column and the second heat conduction column areintegrally formed with the upper shell.
 17. The optical module accordingto claim 7, wherein the shell includes an upper shell and a lower shell,the lower shell includes the first heat conduction column and the secondheat conduction column, and the laser assembly and the silicon opticalchip are disposed on a side of the circuit board close to the lowershell.
 18. The optical module according to claim 1, wherein theprotective cover is bonded to the circuit board through a glue.
 19. Theoptical module according to claim 1, further comprising fixing pins,wherein the protective cover is fixedly connected to the circuit boardthrough the fixing pins.
 20. The optical module according to claim 1,wherein the circuit board includes fixing holes, the protective coverincludes via holes, and the fixing pins pass through the via holes to befitted with the fixing holes to fix the protective cover on the circuitboard.